ESP32 ADC - Read Analog Values with Arduino IDE

 ESP32 ADC - Read Analog Values with Arduino IDE

Hàm sử dụng trong lập trình chức năng đọc ADC:  

analogRead(ADC_pin);

• Chức năng: đọc giá trị analog tại ADC_pin
• Giá trị trả về: 0 -> 2n-1 với n là độ phân giải của bộ ADC ví dụ ADC 10 bit thì trả về giá trị   0  -> 210-1

Theo hình GPIO 15 dùng để đọc ADC vào từ biến trở.

CHƯƠNG TRÌNH ESP32_ARDUINO IDE.

// Mặc định 12 bit

// Potentiometer is connected to GPIO 34 (Analog ADC1_CH6) 

const int GPIO_ADC= 34; // Chân 34 dùng để đọc ADC, gán chân 32 = GPIO_ADC.

// variable for storing the potentiometer value

int GIA_TRI_ADC_DOC_DUOC= 0;

void setup() {

  Serial.begin(115200); // Tốc độ truyền lên, trên arduino IDE phải trùng.

  delay(1000);

}

void loop() {

  // Reading potentiometer value

  GIA_TRI_ADC_DOC_DUOC= analogRead(GPIO_ADC);

  Serial.println(GIA_TRI_ADC_DOC_DUOC);

  delay(500);

}

FUNCTION ADC -  CÁC BẠN CHÚ Ý  NÊN ĐỌC :

• analogReadResolution(resolution): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
• analogSetWidth(width): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
• analogSetCycles(cycles): set the number of cycles per sample. Default is 8. Range: 1 to 255.
• analogSetSamples(samples): set the number of samples in the range. Default is 1 sample. It has an effect of increasing sensitivity.
• analogSetClockDiv(attenuation): set the divider for the ADC clock. Default is 1. Range: 1 to 255.
• analogSetAttenuation(attenuation): sets the input attenuation for all ADC pins. Default is ADC_11db. Accepted values:
  • ADC_0db: sets no attenuation. ADC can measure up to approximately 800 mV (1V input = ADC reading of 1088).
  • ADC_2_5db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1100 mV. (1V input = ADC reading of 3722).
  • ADC_6db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1350 mV. (1V input = ADC reading of 3033).
  • ADC_11db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 2600 mV. (1V input = ADC reading of 1575).
• analogSetPinAttenuation(pin, attenuation): sets the input attenuation for the specified pin. The default is ADC_11db. Attenuation values are the same from previous function.
• adcAttachPin(pin): Attach a pin to ADC (also clears any other analog mode that could be on). Returns TRUE or FALSE result.
• adcStart(pin), adcBusy(pin) and resultadcEnd(pin): starts an ADC convertion on attached pin’s bus. Check if conversion on the pin’s ADC bus is currently running (returns TRUE or FALSE). Get the result of the conversion: returns 16-bit integer.